A concept rooted in centuries of American and English legal tradition is that the commission of a crime requires both a wrongful act and a culpable mental state. The wrongful act (actus reus in Latin) is the physical act committed by a person. The mental state (mens rea) is the person’s guilty state of mind when committing the act. A crime requires a marriage of both factors. As one U.S. Supreme Court justice wrote, “Crime, as a compound concept, generally constituted only from concurrence of an evil-meaning mind with an evil-doing hand[.]” The purpose of this approach was to penalize only those who, when faced with the choice of obeying the law or committing a crime, voluntarily chose to commit a crime.

In 1952, the U.S. Supreme Court issued a landmark decision in the case of Morissette v. United States, in which the court examined the concept of mens rea. While hunting in northern Michigan, the defendant discovered a pile of rusted bomb casings on state property that had been leased to the federal government. Presuming the casings were abandoned, the defendant collected a load to sell as scrap metal. He was subsequently indicted and convicted of stealing federal property. The trial court refused to allow the defendant to argue his innocent intention, and held that the fact the defendant took the casings created a presumption that he meant to steal government property, regardless of his actual intent. On appeal, the U.S. Supreme Court reversed the conviction. The high court held that where a federal statute codifies a common-law crime, courts should construe the statute to include a mens rea element, even when Congress failed to specify a threshold for harmful intent.

With the growth of industrialization and urbanization in the late 19th century, a new form of crime emerged, commonly known as “public welfare” offenses. Legislatures enacted these new crimes under their police power to promote social order. Examples of public welfare regulations included the improper sale of alcohol, sale of adulterated food and drugs or misbranded articles, public nuisances, and violations of traffic, motor vehicle and other laws concerning public safety and public health.

Significantly, public welfare offenses omit the requirement to establish blameworthiness for a criminal conviction; liability can be imposed irrespective of the actor’s intent. The use of public welfare laws to regulate behavior has increased over time, with state legislatures and Congress frequently enacting laws that are silent on the mens rea element of crimes, leaving it to the courts to determine what standard of intent should be applied.

The expansion of public welfare offenses (and the attendant erosion of mens rea) has been widely criticized and raises a number of concerns. Inadequate mens rea provisions result in a vague criminal code, granting prosecutors and the courts a great deal of discretion and creating the potential for inconsistent application. The purpose of the mens rea doctrine was to punish criminally culpable behavior, and by omitting intent provisions, public welfare offenses often regulate and criminalize behavior that would be otherwise unobjectionable, but for the regulatory prohibition. The proliferation of public welfare offenses can place well-intentioned citizens in jeopardy of unwittingly engaging in criminal behavior.

Given the erosion of the mens rea requirement, a number of states have adopted a default mens rea provision in their criminal code. In other words, the state prescribes a default culpability standard where the criminal statute is silent on the intent required to establish a criminal offense. Legislatures in those states are still capable of adopting public welfare regulations, but must do so explicitly.

Michigan’s criminal code does not contain a default mens rea provision. Thus, if Michigan statute does not explicitly state the culpability necessary to establish an offense, courts are left to evaluate whether a mens rea requirement should be inferred or if the defendant should be held strictly liable for the criminal act.

Scores of Michigan misdemeanors and felonies are silent on the mens rea element. These public welfare offenses cover a wide variety of behavior: lobbying by former state lawmakers; the care of pet ferrets; transportation of Christmas trees and Michigan holly; removal of forest products from state lands; disposal of litter produced at health facilities; disposal of used motor oil; disposal of scrap tires; removal of certain abandoned property on the bottomlands of the Great Lakes; and the transportation of loaded firearms. Significant fines and imprisonment can be incurred for violations of these laws.

The Michigan Legislature should expressly affirm the fundamental importance of mens rea and should adopt a default mens rea provision to apply to statutes that fail to clearly define the intent required for a criminal conviction. If a criminal statute is silent on the requisite state of mind to establish a crime, the default mens rea provision would be incorporated. Standardizing the application of mens rea requirements would provide for a more efficient criminal justice system.